realloc

问题 In C can you have realloc inside realloc? For example, a struct inside a struct when you need to malloc both of them and realloc both of them. If yes can someone please provide a simple example? Thank you in advance. 回答1: Your question is not dreadfully clear, but... Yes, a given dynamically allocated structure (for example, an array of structures) can itself contain pointers to allocated data (such as various other arrays of allocated structures), and you can reallocate the various parts

问题 So I was using malloc in my program and then realloc within a method inside the program. After I called this method so many times I would get a "Segmentation fault (core dumped)". Upon further inspection I realized that for some reason when my pointer goes from 0x25d7d60 or 0x223fae0 (or any address represented by 7 digits (0xHHHHHHH) ) to 0x7f47d370a010 (with more than 7 digits) for example, a segfault is thrown from within the realloc call, realloc wont even return NULL. I fixed this by

问题 I have code receiving string data from a socket which crashes on the first iteration: int size_data = 1024*sizeof(char); char *data = malloc(size_data); char *data_aux; int br_aux=0; int *nptr; memset(&data[0], 0, size_data); int br = recv(sockdata, data, size_data, 0); data_aux = malloc(br); while (br>0) { br_aux = br_aux + br; strcat(data_aux, data); br = recv(sockdata,data, size_data, 0); if (br > 0) { nptr = (int *) realloc(data_aux, br+br_aux); } } free(data); printf("%s", data_aux);

问题 I'm trying to dynamically allocate an array to read user input from the command line. It works 99/100 times, but if I type in a bunch of characters repeatedly I will sometimes get a segmentation fault error OR a double free or corruption(fasttop) error. This error is relatively hard to reproduce. I'm pretty sure the error occurs because of the way I'm reallocating the array. while(1){ char *buf_in; // Holds user keyboard input int cnt = 0, length = 0; // cnt stores current read buffer size,

问题 I'm trying to dynamically increase memory of an int array, However I'm having issues getting it to work. It isn't expanding and adding more elements to the array, I'm not sure what I'm doing wrong. Please help! int* fibs = NULL; void genFibs(){ int i = 1,curSize = 0,curNum = 0; int flag = 1; while(flag){ if(curSize != 0 &&curSize != 1){ curNum = fibs[curSize-2]+fibs[curSize-1]; }else if(curSize-1 == 1){ curNum = fibs[curSize-1]+fibs[curSize-1]; }else{ curNum = 1; } if(curNum<=10){ curSize++;

问题 When I run the below code, I get the given output. #include <stdio.h> /* printf */ #include <stdlib.h> /* malloc, realloc */ int main() { char* characters = (char *) malloc(10 * sizeof(char)); printf("Before: characters at %p, size=%lu\n", (void *) characters, sizeof(characters) / sizeof(characters[0])); char* temp = (char *) realloc(characters, 100); if (temp) { printf("After realloc, characters size = %lu, temp size = %lu\n", sizeof(characters) / sizeof(characters[0]), sizeof(temp) / sizeof

问题 Here i am getting some problems in realloc or free in message queue example. In below program i got error of double free or corruption at the time of last message received from the message queue. I send 10 messages in message queue and i received 10 messages at receiver side and its working fine. After receiving every message i am doing free the buf pointer. and its free every time but its getting problem in last time means 10th time. Its given error like double free or corruption how its

问题 So I need to write a function that reads all the elements inside a bit file. The point is that I don't know how many elements there could be inside, but I know what type of elements are. So I tried to write this function: void loadData(Parallelogram **array) { FILE *data; long size; //int numberOfElements = 0; int numberOfObjects = 0; if ((data = fopen(name, "rb"))!=NULL) { fseek(data, 0, SEEK_END); size = ftell(data); fseek(data, 0, SEEK_SET); if (size<(long)sizeof(Parallelogram)) { printf(

问题 I am trying to use realloc to dynamically create instances of a struct, filling it with data from a temporary structure as I go. The program crashes when it reaches the line to malloc a pointer of the structure a second time but I am not sure how I should structure this function. I have the following code: #define MAX_STRING 50 struct data { int ref; int port; char data[MAX_STRING+1]; }valid, invalid; void read_file(FILE *file); void validate(struct data* temp); int g = 0; int main(){ char

问题 Sorry if this has been asked before, I haven't been able to find just what I am looking for. I am reading fields from a list and writing them to a block of memory. I could Walk the whole list, find the total needed size, do one malloc and THEN walk the list again and copy each field; Walk the whole list and realloc the block of memory as I write the values; Right now the first seems the most efficient to me (smallest number of calls). What are the pros and cons of either approach ? Thank you